Process for the manufacture of threads, filaments, bands, or films of a polished and transparent nature, composed of plastic substances



Patented May 14, 1929.

U N l T E D S T A T ES P ALFRED LANDUGCI, F PARIS, FRANCE,

DU PONTPATHE FILM MANUFACTURING CORPORATION, WARE, A CORPORATION OF DELAWARE.

ASSIGNOR, J'BY MESNE .aASSIG'NMEN-TS, "TO

201' WILMINGTON, 'QDELA- PROCESS FOR THE MANUFACTURE or THREADS, *mnamnnms, 13mins, .103 runs OF A POLISHED AND TRANSPARENT NAT one, oomnosnn or 'rrasmre-flsuns'rmcns.

No Drawing. Application filed April .18, 1927,.serial' No.,.18A,834,.andfiniiErannerApflli,4926.

The present invention relates to an improved process for the manufacture of.

threads, filaments, bands or films ot' a pol ished and transparent nature, tromsolutions of cellulose derivatives.

It is a known fact that such cellulosederivatives are dissolved in suitable organic solvents and are then converted into transparent or translucent plastic masses of various forms, by the extraction of said solvents by evaporation, or by precipitation or coagulation by oils. 1

It is further known that the cellulose Iderivatives, such asesters or others are precipitated by water, but in this case opaque plastic masses are obtained.

The present invention relates to a process for the manufacture of threads, filaments,

1})ands or films ot-a polished-and transparent 2 nature from cellulose derivatives such as esters or ethers, which are dissolved in suitable organic solvents,

bath when discharged from the apparatus such as nozzles or dies bywhieh the solution is given a suitable form as required for the manufacture, and further, in that the resulting products are made polished and transparout, without change of form, by a hot vair drying, which is preferably efiected immediately after the coagulation takes place.

I have found that when the coagulation is followed by a prolonged drying by hot air at a suitable temperature which in practice may be between and 80 degrees-(1., a re-polishing efiect will take place which is the sameas.

the one obtained by ours of solvents as specified in my copend- 111g application No. 86,928 of the 8th of Feb- 40 ruary 1926. In this event it is not necessary to employ outside solvents, since the repolishing is performed by the solvents which are still contained in the products from the coagulation process, and the heat starts the action of such solvents. In fact, when issuing from the coagulation apparatus, the

products contain alarge proportion of solvents, and it at this time the said products are strongly heated, the discharge of the sol- Vents contained in the said products will take place through the material and will dissolvethe opaque surface layers in a manner analogous to the dissolving action of new solfacture, and

which is characterized in that the solution is 'coagulated 1n an aqueous means of solvents or vavents .ortheir vaporus andathesaid products will thus become transparent.

Th1snew processthasthe:advantageofipermittmg a :very rapid :-and inexpensivemanu- .a complete and ready recovery I o f the solvents,zand'lacan'readily-zobtainjproducts possessing .remarkableaqualities:of transparency, brilliancy, flexibility and strength. A great variety of .organic' sgilvents may be employed ,for dissplving the. cellulose derivatives, and it is simply necessarythat they shall be soluble inor:niiscible withfthefaqueo'us coagulating bat-h.

For :the said aqueous 'bath' we may employ water orvsuitableia ueous ;s,olut-ionssuch ras aqueous solutions; 0 alcohols or of solvents afor thecellulose derivatives, .01 solutions :of .salts, such asso di'um or calcium chloride, so-

dium nitrate or the like.

After the precipitation ghas v:taken place, the coagulating aqueous ibath will :contain almost the whole of the organic solvents which served to dissolve the cellulose dezrivat-ives aandwhich .ama y be recovered by known'means', I a

The presence of substances conferring plasticity or of loa lutions of; the cellulose derivativesrwlill make 110. ch ange. inathe application of the present process,-:nor willtthe latter bee-attracted by the methods .andapparatus :usedoforpotiring :the solutions -ofitheyce1lulose derivatives intof-the coagulating aqueous baths.

"It .may however happen in certain cases, for instance when the .collodions contain .a large amount of water, that the; product will ingQbut-everi in this :case tthe rresult :obtained -will be quiteapprec'iable. '..lln this 'event, I may obtain a perfect transparency andzpolrish by sub]ec'ting-the ;product,.,zafter dryin in .a chamber, to the "regulated action 0 ding-material in the *sonot be ma'deentirely transparent by this dry-- proper sol-vents 'wliioh:act inf-the state of liquid'or vapor, as speoi'fieidiinmy aforesaid copend-ing patentapplicationINo; 86,928-of the 8th of February 1926.

' In conformity to the present invention, and by Way "of'exampl'e, the. operation may be performed :as follows:

Example. tfiCflt0I1B-.-S0ll1tl01l of nitrocellulose =or acetate of cellulose-is discharged from .a small orifice iand j's1then1in :immediate contactwvith verywctild water at 4 :to :10

degrees C., for example. The precipitation is complete after 1 or 2 minutes, according to the diameter of the stream. The resulting opaque filament is dried in hot air in a chamber which is maintained at 40-80 degrees C. The opacity disa pears, and this affords a filament whose rilliancy, flexibility and strength are quite remarkable.

Example 2.A solution of nitro-cellulose in an alcohol-acetone solvent is poured in a continuous sheet upon a well-polished wheel which is .partially immersed in a vessel of water. When it makes contact with this water, which is constantly renewed, the nitrocellulose solution is precipitated. The resulting film isstripped from its support, and is placed in a hot air drying chamber which is maintained at 40-80 degrees (1, so that the water will be evaporated, and the film ecomes quite transparent. I

Example 5.In a modification of the latter example, the sheet of nitro-cellulose collodion .is poured directly into a vessel of water in which the sheet becomes solid; the resulting film is seized and drawn forward by rollers disposed on the bottom of the said vessel. The other operations may be the same as indicated in Example 2.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. Process for manufacturing articles of plastic material which consists in dissolving a collulose dirivative in an organic solvent, giving to the said-solution the desired shape, coagulating the said solution in an aqueous bath whereby a more or less opaque product is obtained and subjecting the product prior to any other treatment thereof to a hot air drying for a sufficiently long time to make said product transparent and polished.

2. Process for manufacturing articles of plastic material which consistsin dissolving a cellulose derivative in an or anie solvent, giving to the said solution the esired shape, coagulating the said solution in an aqueous bath whereby a more or less opaque product is obtained, and subjecting the product prior to any other treatment thereof to a hot air drying at a temperature comprised between 40 and 80 (3., for a sufficiently long time to make said polished.

3. Process for manufacturing articles of plastic material which consists in dissolving a cellulose'derivative in an organic solvent, giving to the said solution the desired shape, coagulating the said solution in an aqueous bath with which said organic solvent is miscible, whereby is obtained, and subjecting the product prior to any other treatment thereof to a hot air drying for a sufiiciently long time to make said product transparent and polished.

4. Process for manufacturing articles of plastic material which consists in dissolving a cellulose derivative in an organic solvent, giving to the said solution the desired shape, coagulating the said solution in water whereby a more or less opa ue product is obtained, and subjecting the product prior to any other treatment thereof to a hot air drying for a sufficiently long time to make said product transparent and polished.

5. Process for manufacturing articles of plastic material which consists in dissolving a cellulose derivative in acetone, giving to the said solution the desired shape, coagulating the said solution in an aqueous bath, whereby a. more or less opaque product is obtained, and subjecting the product prior to any other treatment thereof to, a hot airdrying for a sufficiently long time to make said product transparent and polished.

In testimony whereof I have signed my name to this specification.

ALFRED LANDUCCI.

a more or less opaque product product transparent and 

